Erratum in

Abstract

PURPOSE:

To implement and characterize a fluorine-19 ((19)F) magnetic resonance imaging (MRI) technique and to test the hypothesis that the (19)F MRI signal in steady state after intravenous injection of a perfluoro-15-crown-5 ether (PCE) emulsion may be exploited for angiography in a pre-clinical in vivo animal study.

MATERIALS AND METHODS:

In vitro at 9.4T, the detection limit of the PCE emulsion at a scan time of 10 min/slice was determined, after which the T(1) and T(2) of PCE in venous blood were measured. Permission from the local animal use committee was obtained for all animal experiments. 12 µl/g of PCE emulsion was intravenously injected in 11 mice. Gradient echo (1)H and (19)F images were obtained at identical anatomical levels. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were determined for 33 vessels in both the (19)F and (1)H images, which was followed by vessel tracking to determine the vessel conspicuity for both modalities.

RESULTS:

In vitro, the detection limit was ∼400 µM, while the (19)F T(1) and T(2) were 1350±40 and 25±2 ms. The (19)F MR angiograms selectively visualized the vasculature (and the liver parenchyma over time) while precisely coregistering with the (1)H images. Due to the lower SNR of (19)F compared to (1)H (17±8 vs. 83±49, p<0.001), the (19)F CNR was also lower at 15±8 vs. 52±35 (p<0.001). Vessel tracking demonstrated a significantly higher vessel sharpness in the (19)F images (66±11 vs. 56±12, p = 0.002).

CONCLUSION:

(19)F magnetic resonance angiography of intravenously administered perfluorocarbon emulsions is feasible for a selective and exclusive visualization of the vasculature in vivo.

Three series of 3 in vivo mouse images, with 1H reference images in the left column, 19F images in the middle and a color image fusion of the two in the right column.

a–c) axial slice through the heart, with a ECG-triggered to counter motion blurring, which is not needed in b because of the averaging (RV = right ventricle, LV = left ventricle, AA = abdominal aorta). d–f) Coronal slice through the lungs (dark at the top), DA and the kidneys (at the bottom), where the renal artery (RA) can be discerned. g–i) Axial slice at the level of the liver. In h, the hepatic artery (HA) and several others can be discerned while PCE is also temporarily stored in the surrounding liver tissue, thus decreasing the conspicuity of the vessels. j–l) Coronal slice through the abdominal aorta. Varying vessel contrast can be observed in j, which is not present in k.

Distribution of crown ether in the vasculature of the thorax in a mouse in vivo, 3h after injection.

Shown here is a 19F MRA coronal maximum intensity projection created from 6 adjacent slices with a thickness of 2mm each. The image shows the lumen of several cardiovascular structures including the right ventricle (RV), left ventricle (LV), abdominal aorta and vena cava (AA+VC), and a renal artery (RA), as well as the liver (L).